Multiple substrate microelectronic devices and methods of manufacture

Abstract

A microelectronic device and method for manufacture. In one embodiment, two microelectronic substrates are directly bonded to each other without an intermediate adhesive material. For example, each microelectronic substrate can include a first surface, a second surface opposite the first surface, and a functional microelectronic feature coupled to a connection terminal of the microelectronic substrate. The connection terminals can be coupled to a support member, such as a leadframe or a printed circuit board, with the bond plane between the microelectronic substrates either aligned with or transverse to the support member. The microelectronic substrates can be enclosed in a protective packaging material that can include a transparent window to allow selected radiation to strike one or the other of the microelectronic substrates.

1. A method for forming a compound microelectronic device, comprising:
 forming a first microelectronic substrate having a first surface, a second surface opposite the first surface, a first operable microelectronic device, and a first connection terminal coupled to the first microelectronic device; 
 forming a second microelectronic substrate having a first surface, a second surface opposite the first surface, a second operable microelectronic device, and a second connection terminal coupled to the second microelectronic device; and 
 bonding the first and second microelectronic substrates together by placing the second surface of the second microelectronic substrate directly against the first or second surface of the first microelectronic substrate without an adhesive between the first and second microelectronic substrates. 
 
     
     
       2. The method of  claim 1 , further comprising packaging the first and second microelectronic substrates together by encapsulating the microelectronic substrates in a single enclosure without other microelectronic substrates. 
     
     
       3. The method of  claim 1 , further comprising forming the first functional microelectronic device to include an electronic memory device. 
     
     
       4. The method of  claim 1 , further comprising forming the first and second microelectronic substrates to each have at least 128 megabits of memory. 
     
     
       5. The method of  claim 1 , further comprising removing material from the second surface of the first microelectronic substrate to reduce a thickness of the first microelectronic substrate in a direction transverse to the second surface after bonding the first and second microelectronic substrates. 
     
     
       6. The method of  claim 1 , further comprising selecting the first and second microelectronic substrates to be microelectronic dies separated from one or more microelectronic wafers. 
     
     
       7. The method of  claim 1  wherein the first and second microelectronic substrates are microelectronic wafers, further comprising separating the wafers into bonded pairs of dies after bonding the wafers together. 
     
     
       8. The method of  claim 1 , further comprising:
 supporting the first and second microelectronic substrates on a conductive support member; and 
 electrically coupling the first and second connection terminals to the conductive support member. 
 
     
     
       9. The method of  claim 1  wherein the first and second microelectronic substrates each have an intermediate surface between the first and second surfaces, further comprising:
 coupling the connection terminal of the first microelectronic substrate to a first bond site on the intermediate surface of the first microelectronic substrate; 
 coupling the connection terminal of the second microelectronic substrate to a second bond site on the intermediate surface of the second microelectronic substrate; and 
 attaching the first and second microelectronic substrates as a unit to a support member with the intermediate surfaces of the microelectronic substrates facing toward the support member. 
 
     
     
       10. The method of  claim 1  wherein bonding the first and second microelectronic substrates together includes placing the second surface of the second microelectronic substrate directly against the first surface of the first microelectronic substrate with the first connection terminal facing the same direction as the second connection terminal. 
     
     
       11. The method of  claim 1  wherein bonding the first and second microelectronic substrates together includes placing the second surface of the second microelectronic substrate directly against the second surface of the first microelectronic substrate with the first connection terminal facing away from the second connection terminal. 
     
     
       12. The method of  claim 1 , further comprising strengthening the bond between the first and second microelectronic substrates by elevating the temperature of the first and second microelectronic substrates after bonding the first and second microelectronic substrates. 
     
     
       13. The method of  claim 1 , further comprising strengthening the bond between the first and second microelectronic substrates by placing the first and second microelectronic substrates under pressure after bonding the first and second microelectronic substrates. 
     
     
       14. A method for forming a packaged compound microelectronic device, comprising:
 forming a first microelectronic substrate having a first surface, a second surface opposite the first surface, a first operable microelectronic device, and a first connection terminal at the first surface coupled to the first microelectronic device; 
 forming a second microelectronic substrate having a first surface, a second surface opposite the first surface, a second operable microelectronic device, and a second connection terminal at the first surface coupled to the second microelectronic device; 
 bonding the first and second microelectronic substrates together by placing the second surface of the first microelectronic substrate directly against the second surface of the second microelectronic substrate without an adhesive between the first and second microelectronic substrates; 
 engaging at least one of the first and second microelectronic substrates with a conductive support member; 
 electrically coupling the first and second connection terminals to the conductive support member; and 
 packaging the first and second microelectronic substrates together by surrounding both microelectronic substrates with a single package enclosure. 
 
     
     
       15. The method of  claim 14  wherein the support member includes a plurality of elongated support portions having a first end toward the first and second microelectronic substrates and a second end spaced apart from the first end, further comprising forming connector pins with the elongated support portions by bending the elongated support portions proximate to the second ends thereof. 
     
     
       16. The method of  claim 14  wherein surrounding both microelectronic substrates includes encapsulating the microelectronic substrates with a conformal coating. 
     
     
       17. The method of  claim 14  wherein electrically coupling the first connection terminal includes bonding a length of wire between the first connection terminal and the support member. 
     
     
       18. The method of  claim 14 , further comprising disposing a layer of adhesive between the support member and at least one of the first and second microelectronic substrates. 
     
     
       19. The method of  claim 14  wherein engaging at least one of the first and second microelectronic substrates with the support member includes positioning the support member beneath the first and second microelectronic substrates. 
     
     
       20. The method of  claim 14  wherein engaging at least one of the first and second microelectronic substrates with the support member includes positioning the support member above the first and second microelectronic substrates. 
     
     
       21. A method for forming a compound microelectronic device, comprising:
 forming first and second microelectronic substrates to each have a first surface, a second surface opposite the first surface, an operable microelectronic device, and a connection terminal at the first surface coupled to the microelectronic device; 
 bonding at least a first part of the first microelectronic substrate to at least a second part of the second microelectronic substrate by placing the second surface of the first microelectronic substrate directly against the second surface of the second microelectronic substrate without an adhesive between the first and second microelectronic substrates; 
 coupling the connection terminal of the first microelectronic substrate to a first bond site on an intermediate surface of the first microelectronic substrate between the first and second surfaces of the first microelectronic substrate; 
 coupling the connection terminal of the second microelectronic substrate to a second bond site on an intermediate surface of the second microelectronic substrate between the first and second surfaces of the second microelectronic substrate; and 
 attaching the first part of the first microelectronic substrate and the second part of the second microelectronic substrate as a unit to a support member with the intermediate surfaces of the microelectronic substrates facing toward the support member. 
 
     
     
       22. The method of  claim 21  wherein the first microelectronic substrate includes a first wafer, the first part of the first microelectronic substrate includes a first die of the first wafer, the second microelectronic substrate includes a second wafer and the second part of the second microelectronic substrate includes a second die of the second wafer, further comprising separating the first die from the first wafer and separating the second die from the second wafer. 
     
     
       23. A method for forming a microelectronic device, comprising:
 forming a first microelectronic substrate to have a first surface, a second surface opposite the first surface, an intermediate surface between the first and second surfaces, a first operable microelectronic device, and a first connection terminal at the intermediate surface coupled to the first microelectronic device; 
 forming a second microelectronic substrate to have a first surface, a second surface opposite the first surface, an intermediate surface between the first and second surfaces, a second operable microelectronic device, and a second connection terminal at the intermediate surface coupled to the second microelectronic device; and 
 bonding at least a first part of the first microelectronic substrate to at least a second part of the second microelectronic substrate by placing the second surface of the first microelectronic substrate directly against the second surface of the second microelectronic substrate without an adhesive between the first and second microelectronic substrates. 
 
     
     
       24. The method of  claim 23 , further comprising packaging the first and second microelectronic substrates together by surrounding both microelectronic substrates with a single package enclosure. 
     
     
       25. The method of  claim 23  wherein the first microelectronic substrate includes a first wafer, the first part of the first microelectronic substrate includes a first die of the first wafer, the second microelectronic substrate includes a second wafer and the second part of the second microelectronic substrate includes a second die of the second wafer, further comprising separating the first die from the first wafer and separating the second die from the second wafer. 
     
     
       26. The method of  claim 25  wherein separating the first die from the first wafer occurs after bonding the first wafer to the second wafer. 
     
     
       27. The method of  claim 25  wherein separating the first die from the first wafer occurs before bonding the first part of the first microelectronic substrate to the second part of the second microelectronic substrate. 
     
     
       28. The method of  claim 23 , further including attaching the first part of the first microelectronic substrate to the second part of the second microelectronic substrate to a support member by attaching a first solder ball between the support member and the first connection terminal of the first microelectronic substrate and attaching a second solder ball between the support member and the second connection terminal of the second microelectronic substrate. 
     
     
       29. The method of  claim 28 , further comprising selecting the support member to include a printed circuit board. 
     
     
       30. A method for forming a packaged compound microelectronic device, comprising:
 forming a first microelectronic substrate having a first surface, a second surface opposite the first surface, a first operable microelectronic device, and a first connection terminal at the first surface coupled to the first microelectronic device; 
 forming a second microelectronic substrate having a first surface, a second surface opposite the first surface, a second operable microelectronic device, and second connection terminal at the first surface coupled to the second microelectronic device; 
 bonding the first and second microelectronic substrates together by placing the second surface of the second microelectronic substrate directly against the first surface of the first microelectronic substrate without an adhesive between the first and second microelectronic substrates; and 
 packaging the first and second microelectronic substrates together by surrounding both microelectronic substrates with a single package enclosure. 
 
     
     
       31. The method of  claim 30 , further comprising selecting the second microelectronic substrate to have a smaller planform shape than the first microelectronic substrate. 
     
     
       32. The method of  claim 30 , further comprising coupling the first and second connection terminals to a leadframe. 
     
     
       33. The method of  claim 30 , further comprising coupling the first and second connection terminals to a printed circuit board. 
     
     
       34. The method of  claim 30 , further comprising connecting the first connection terminal to the second connection terminal. 
     
     
       35. A method for forming a compound microelectronic device, comprising:
 forming a first microelectronic substrate having a first surface, a second surface opposite the first surface, a first operable microelectronic feature, and a first connection terminal coupled to the first microelectronic feature; 
 forming a second microelectronic substrate having a first surface, a second surface opposite the first surface, a second operable microelectronic feature, and a second connection terminal coupled to the second microelectronic feature; and 
 bonding the first and second microelectronic substrates together by placing the second surface of the second microelectronic substrate directly against the first or second surface of the first microelectronic substrate without an adhesive between the first and second microelectronic substrates. 
 
     
     
       36. The method of  claim 35 , further comprising packaging the first and second microelectronic substrates together by encapsulating the microelectronic substrates in a single enclosure without other microelectronic substrates. 
     
     
       37. The method of  claim 35 , further comprising forming the first functional microelectronic feature to include an electronic memory device. 
     
     
       38. The method of  claim 35 , further comprising selecting the first and second microelectronic substrates to be microelectronic dies separated from one or more microelectronic wafers. 
     
     
       39. A method for forming a compound microelectronic device, comprising:
 forming a first microelectronic substrate having a first surface, a second surface opposite the first surface, a first operable microelectronic device, and a first connection terminal coupled to the first microelectronic device; 
 forming a second microelectronic substrate having a first surface, a second surface opposite the first surface, a second operable microelectronic device, and a second connection terminal coupled to the second microelectronic device; and 
 bonding the first and second microelectronic substrates together by placing the second surface of the second microelectronic substrate directly against the first or second surface of the first microelectronic substrate without an adhesive between the first and second microelectronic substrates. 
 
     
     
       40. The method of  claim 39 , further comprising packaging the first and second microelectronic substrates together by encapsulating the microelectronic substrates in a single enclosure without other microelectronic substrates. 
     
     
       41. The method of  claim 39  wherein the first and second microelectronic substrates are microelectronic wafers, further comprising separating the wafers into bonded pairs of dies after bonding the wafers together. 
     
     
       42. A method for forming a compound microelectronic device, comprising:
 forming a first microelectronic substrate having a first surface, a second surface opposite the first surface, a first operable microelectronic device, and a first connection terminal coupled to the first microelectronic device; 
 forming a second microelectronic substrate having a first surface, a second surface opposite the first surface, a second operable microelectronic device, and a second connection terminal coupled to the second microelectronic device; and 
 removing material from the second surfaces of the first and second microelectronic substrates by chemically and/or chemically-mechanically planarizing the second surfaces; and 
 bonding the first and second microelectronic substrates together by placing the second surface of the second microelectronic substrate directly against the first or second surface of the first microelectronic substrate without an adhesive between the first and second microelectronic substrates. 
 
     
     
       43. The method of  claim 42 , further comprising packaging the first and second microelectronic substrates together by encapsulating the microelectronic substrates in a single enclosure without other microelectronic substrates. 
     
     
       44. The method of  claim 42  wherein the first and second microelectronic substrates are microelectronic wafers, further comprising separating the wafers into bonded pairs of dies after bonding the wafers together.